It is an object to provide a magnetic recording medium that enables good reproduction even after long-term preservation and that has a small overall thickness.The present technology provides a tape-shaped magnetic recording medium including a magnetic layer, a ground layer, a base layer, and a back layer, in which an average thickness tT of the magnetic recording medium is equal to or less than 5.3 μm, and, when the magnetic recording medium is subjected to dynamic viscoelasticity measurement at a frequency of 10 Hz and a temperature rise rate of 2° C./min, a difference between a maximum and a minimum of a viscosity term E″ in a temperature range of 0° C. to 80° C. is equal to or less than 0.18 GPa. In addition, the present technology also provides a tape cartridge including the tape-shaped magnetic recording medium.
Legal claims defining the scope of protection, as filed with the USPTO.
2. The magnetic recording medium according to claim 1, wherein, when the magnetic recording medium is subjected to the dynamic viscoelasticity measurement, a difference between a maximum and a minimum of the viscosity term E″ in a temperature range of 40° C. to 80° C. is equal to or less than 0.10 GPa.
3. The magnetic recording medium according to claim 1, wherein, when the magnetic recording medium is subjected to the dynamic viscoelasticity measurement, a temperature at which a maximum of the viscosity term E″ of the magnetic recording medium in −10° C. to 140° C. is measured is in a range of 0° C. to 80° C.
5. The magnetic recording medium according to claim 1, wherein, when the magnetic recording medium is subjected to the dynamic viscoelasticity measurement, a difference between a maximum and a minimum of the viscosity term E″ in a temperature range of 0° C. to 80° C. is 0.13 to 0.17 GPa.
6. The magnetic recording medium according to claim 1, wherein, when the magnetic recording medium is subjected to the dynamic viscoelasticity measurement, a temperature at which a minimum of the viscosity term E″ of the magnetic recording medium in −10° C. to 140° C. is measured is in a range of 0° C. to 80° C.
8. The magnetic recording medium according to claim 1, wherein, when the magnetic recording medium is subjected to the dynamic viscoelasticity measurement, a difference between a maximum and a minimum of the viscosity term E″ in a temperature range of 0° C. to 80° C. is equal to or less than 0.12 GPa.
10. The magnetic recording medium according to claim 1, wherein, when the magnetic recording medium is subjected to the dynamic viscoelasticity measurement, a difference between a maximum and a minimum of an elasticity term E′ in a temperature range of 0° C. to 80° C. is equal to or less than 1.5 GPa.
11. The magnetic recording medium according to claim 1, wherein, when the magnetic recording medium is subjected to the dynamic viscoelasticity measurement, a difference between a maximum and a minimum of an elasticity term E′ in a temperature range of 0° C. to 80° C. is equal to or less than 0.5 GPa.
12. The magnetic recording medium according to claim 1, wherein a thickness of the base layer is equal to or less than 4.2 μm.
13. The magnetic recording medium according to claim 1, wherein a thickness of the base layer is equal to or less than 4.0 μm.
14. The magnetic recording medium according to claim 1, wherein a length of the magnetic recording medium in a longitudinal direction is equal to or more than 1,000 m.
15. The magnetic recording medium according to claim 1, wherein a squareness ratio in a perpendicular direction is equal to or less than 65%.
16. The magnetic recording medium according to claim 1, wherein an average thickness tm of the magnetic layer is equal to or less than 80 nm.
17. The magnetic recording medium according to claim 1, wherein an average thickness tm of the magnetic layer is equal to or less than 50 nm.
18. The magnetic recording medium according to claim 1, wherein the magnetic layer includes a magnetic powder, and the magnetic powder contains hexagonal ferrite, ε iron oxide, or Co-containing spinel ferrite.
19. The magnetic recording medium according to claim 14, wherein the hexagonal ferrite contains at least one of Ba or Sr, and the ε iron oxide contains at least one of Al or Ga.
20. The magnetic recording medium according to claim 1, wherein a coercive force Hc in a longitudinal direction is equal to or less than 2,000 Oe.
21. The magnetic recording medium according to claim 1, wherein the magnetic layer is configured to be able to record data such that a minimum of a magnetization reversal interval L is equal to or less than 48 nm.
22. The magnetic recording medium according to claim 1, wherein the magnetic layer includes a magnetic powder, and an average aspect ratio of the magnetic powder is from 1.0 to 3.5.
23. The magnetic recording medium according to claim 1, wherein the magnetic layer includes a magnetic powder, and an average particle size of the magnetic powder is equal to or less than 50 nm.
24. The magnetic recording medium according to claim 1, wherein the magnetic layer includes a magnetic powder, and an average particle volume of the magnetic powder is equal to or less than 1,500 nm3.
25. The magnetic recording medium according to claim 1, wherein the magnetic layer includes a magnetic powder, and an average particle volume of the magnetic powder is equal to or less than 1,300 nm3.
26. The magnetic recording medium according to claim 1, wherein the average thickness tT of the magnetic recording medium is equal to or less than 5.2 μm.
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June 17, 2020
June 27, 2023
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